The following patents are described to show some of the prior art.
U.S. Pat. No. 5,269,947, relates to a processor comprising means for mixing a process material with a process liquid (such as water) and forming an emulsion or slurry. Means is provided for pressuring and heating the slurry, and the slurry is then fed to means for quickly reducing the pressure to a relatively low value and further increasing the temperature. The rapid drop in pressure and increase in temperature causes volatile components of the slurry to convert to a gas and separate from the remainder of the slurry which is removed from the processor in the form of solids. The gas is fed to one or more condensers which separate the gas into useful liquids such as various grades of oil.
U.S. Pat. No. 5,431,702 is for a process for time production of fuel pellets or briquettes from sewage sludge solids and municipal solid waste with minimal drying requirements. In one of its more specific aspects, this invention relates to a solid pelleted or briquetted fuel product consisting essentially of sewage sludge solids, waste paper and/or refuse derived fuel, and crushed coal, and to its method of preparation. In still another of its specific aspects, this invention relates to a method for the production of fuel gases from sewage sludge solids and cellulosic wastes.
U.S. Pat. No. 5,104,419, discloses a process for converting solid waste into a synthesis suitable for producing liquid fuel, comprising (a) partially oxidizing and combusting solid waste material in a closed combustion zone at a temperature of 800 degrees to 1000 degrees C., and at a pressure below ambient to produce combustion gases by introducing into the combustion zone a gaseous oxidant comprising oxygen having a purity of at least 95% by volume and carbon dioxide in an oxygen to carbon dioxide ratio, by volume, of about 50:50, (b) conducting the combustion gases, oxygen and carbon dioxide through the solid waste material; (c) withdrawing a producer gas comprising the combustion gases and any unreacted oxygen and carbon dioxide; (d) removing particulate matter from the producer gas; (e) separating carbon dioxide from the producer gas and recycling a portion of the separated carbon dioxide to the combustion zone; (f) separating the less volatile, condensable components of the carbon dioxide-free producer gas, from the more volatile, non-condensable synthesis gas components thereof, and (g) compressing the produced gas at some time prior to the completion step (e). In a preferred embodiment, the more volatile components and at least a portion of the separated carbon dioxide from step (e) are admixed and the resulting a mixed gas mixture is reacted to form methanol. Preferably, the less volatile components are converted by chemical reaction to hydrogen and the hydrogen is recycled into a mixture with the produced gas at some time prior to the commencement of step (e).
U.S. Pat. No. 4,787,321 is directed to a solid waste conversion plan for the conversion of such solid waste as old tires to a gas or liquid hydrocarbon product, wherein the partial pyrolysis of the solid waste is carried out in a reactor having a grate in the lower section and a plurality of rotating fingers extending through the grate for preventing compaction of the solid waste in the reactor. The reactor, a heat exchange means and a stripper are connected in series. A blower is positioned between the heat exchange means and stripper for drawing oxygen-containing gas into the reactor and removing the gases formed therein and passing those gases through the heat exchange means and into the stripper.
U.S. Pat. No. 4,152,122, is defined as an improved system for producing methane-containing product gas by the hydrogasification process. With the system, solid municipal waste is comminuted and dried following which it is introduced to the lock hopper receivers for transference to an elongate hydrogasification reactor. Synthesis gas is introduced to a lower region of the reactor and the comminuted waste, including inorganic materials, is dried and converted to methane-containing product gas and char. The char is removed from the system by a variety of separation systems including cyclone separators or aspirators and the inorganic fractured waste materials pass through the reactor but are undamaged and in a sterile condition ideally suited for recovery. A gasification reactor is incorporated with the system which receives char from the process as well as oxygen to produce the synthesis gas utilized in the hydrogasification reactor. Where no inorganic materials are present, the organic materials may be introduced both to the gasification reactor to produce synthesis gas as well as to the hydrogasification reactor to produce char end product gas. The char is removed from the product gas and returned to the synthesis gas producing gasification reactor. Drying may be carried out utilizing a fluidized sand bed drying technique.